mail.lan.ua has no NS records.
NS records for this zone are defined at lan.ua.
NS records for this zone are defined at lan.ua.
Question and response
Question
dig mail.lan.ua. NS
Answer
The response has no answer records.
Authority
lan.ua. 900 SOA nsa1.srv53.net. support.dnshosting.org. 1772205985 1800 600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0